It is known to provide passive entry and passive starting (PEPS) systems for motor vehicles. The vehicle user typically carries a key fob which can communicate with a base station in the vehicle. The key fob remains in a very low power state to conserve its internal battery. Upon receipt of an initiating trigger (for example when a vehicle door handle is operated), the base station emits a powerful Low Frequency (LF) electromagnetic field, the energy from which wakes up the key fob using a charge pump technique. Once awake, the key fob can then respond to a challenge using Radio Frequencies (RF). The key fob sends a response signal which is validated by the base station to authenticate the key fob. If the key fob is authenticated, the base station actuates a door lock to unlock the door.
The energy required from the vehicle to generate the LF field is considerable, which is why a trigger is universally employed to begin the process. Moreover, the consequence of using an initiating trigger is that the whole sequence of validating the key fob's identity and unlocking the vehicle has to be extremely short to avoid a customer experiencing a delay in the vehicle's response. To help avoid any such delay, a fast-release motor can be provided to unlock the door to provide seamless operation as if the vehicle was already unlocked.
The present invention attempts to address or ameliorate at least some of the above problems associated with known vehicle access systems.